Refuse management system and method

ABSTRACT

A refuse management system (10) has a refuse container (18) associated with a compactor (20) for compacting refuse in the container (18) at a local position, a local controller (26) for receiving and transmitting signals from the compactor, and a processor (14) at a remote position for receiving and processing signals from the local controller (26). A transmitter/receiver is positioned at each of the local and remote positions for establishing two-way communication between the local controller and the remote processor such that the controller and processor can each send and receive signals from each other. A local display (22, 90) is in communication with the controller (26) for displaying signals from the controller and signals received in the controller from the processor to thereby display container condition. A keypad (82) can be provided with the local display (22, 90) and controller for entering data into the controller and displaying data on the display. Preferably, the keypad has function keys (84) for entering and displaying data representative of system parameters and conditions, and scroll keys (86, 88) for scrolling through the da on the display. Methods of determining the condition of the compactor and refuse container are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/016,442 filed on Apr. 29, 1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to refuse management systems, and moreparticularly to management systems for refuse compactors.

2. Description of the Related Art

Many large retail establishments own or lease refuse compactor systems.These systems usually include a trash compactor unit secured to acontainer. The container is separable from the compactor unit and can beloaded for transportation by truck to a landfill. Although containersvary in size, a container in common use can typically hold 40 cubicyards of compacted material. When the container is full, the retailestablishment typically schedules a refuse hauling service to remove andempty the container. The hauling service sometimes exchanges an emptycontainer for the full container at the retail establishment site toavoid interruption of the establishment's activities. Typically, anindicator light is located on the compactor to inform a user when thecontainer is full. The light is illuminated in response to a pressurethat meets or exceeds the preset maximum hydraulic pressure, theassumption being that the compactor cannot crush any further refuse intothe container. However, the light can illuminate falsely when unusuallyhard refuse, such as wooden pallets, are deposited in the container. Inaddition, retail clerks responsible for loading the container andoperating the compactor often fail to pay attention to the light whenilluminated. Consequently, refuse backs up into storage areas of theretail establishment otherwise reserved for product shipments until ahauler can be scheduled to empty the container. This problem isaugmented on weekends when many refuse hauling companies are closed. Asa result, many establishments have the container emptied on a regularbasis, whether or not the container is full. However, landfills oftencharge a standard rate for the size of the container, regardless of theactual amount of refuse disposed. Thus, the retail establishment issubject to additional unnecessary charges from both the hauling companyand the landfill.

A refuse management system currently in use has attempted to overcomethese problems by the provision of a programmable logic controller (PLC)installed at the compactor site. The PLC gathers, sorts, and storesinformation about the compactor's operation. A computer at a remotelocation can access the information stored in the PLC when prompted by acomputer operator. The information can then be downloaded and printedinto a report. The report is analyzed by a person knowledgeable instatistical analysis and the particular parameters of the compactor inreview. The person must then determine when the container will be fulland make arrangements with the hauling company to pick up the container.However, the information gathered by the PLC at the compactor site isnot available to the end user. The end user does not know what decisionshave been made and therefore cannot accurately schedule for compactordown time.

Another problem associated with the current system occurs frequentlywhen the refuse container is removed for dumping. A proximity sensornormally senses the container's presence. When the container is pulled,the proximity sensor is actuated and some of the values stored in thePLC representative of the compactor system conditions, such as averagepressure, amount of usage since last pull, etc., are reset. However, thecompactor and its associated PLC are sometimes disconnected from theirelectrical source when the container is separated from the compactor,and reconnected after the empty container and compactor are rejoined.The proximity sensor in this circumstance does not generate a signal toreset the current values. As a result, the currently stored values areinaccurate and can be interpreted erroneously.

SUMMARY OF THE INVENTION

These and other problems of the prior art are overcome by the provisionof a refuse management system having a local display for notifying anend user when the container is scheduled for hauling. According to oneaspect of the invention, the local display is accessible from a remotelocation.

According to a further aspect of the invention, a method and system areprovided for determining when the container has been pulled, even whenthe proximity sensor fails. The pressure of the compactor is monitoredover a plurality of uses. When the average pressure falls below apredetermined lower limit, it is determined that the container wasemptied, and a signal is generated to reset certain of the compactorparameters.

According to the invention, a method of determining the condition of arefuse container having a compactor associated therewith for compactingrefuse in the container, includes operating the compactor to compactrefuse in the container; measuring at least one pressure applied to thecontainer by the compactor during at least one operation of thecompactor; and calculating a first pressure percentage by dividing themeasured pressure by a predetermined pressure limit. The first pressurepercentage is reflective of the amount of used space in the refusecontainer.

According to another aspect of the invention, a second pressurepercentage is calculated by subtracting the first pressure percentagefrom unity. The second pressure percentage is reflective of the amountof available space in the refuse container for holding more refuse.

According to an even further aspect of the invention, a plurality ofpressures are measured during a corresponding plurality of compactoroperations. An average pressure is determined from the plurality ofpressures and then divided by the predetermined pressure limit to obtainthe first pressure percentage. Preferably, the predetermined pressurelimit is the maximum pressure applied by the compactor when thecontainer is full.

The remaining times that the compactor can be actuated (the remainingusage) is obtained by determining a first usage of the compactor duringa pull interval between an empty container condition and a fullcontainer condition when the container is pulled for dumping multiplyingthe second pressure percentage by the first usage. A time at which thecontainer is full can also be forecasted by determining a plurality ofsecond usages of the compactor for a corresponding plurality ofsequential time intervals and comparing the remaining usage with atleast one of the second usages. Preferably, the first usage is anaverage first usage taken over a plurality of pull intervals. Theplurality of sequential time intervals defines a time group and each ofthe second usages is an average second usage taken over a plurality oftime groups. In one embodiment, each time interval is a day and eachtime group is a week. In a further embodiment, each time interval is anhour and each time group is a work shift.

According to another aspect of the invention, a method for detectingcontainer replacement in a refuse management system includes operating acompactor to compact refuse in the container; measuring a plurality ofpressures applied to the container by the compactor during a pluralityof corresponding compactor operations; calculating an average pressurefor the plurality of measured pressures; comparing the average pressurewith a low pressure set point; and determining that the container hasbeen replaced if the average pressure is below the low pressure setpoint.

Before making a final determination of container replacement, the numberof times that the compactor has been used since the last known containerpull is compared with a minimum usage set point. If the compactor usageis above the minimum usage set point, it is determined that thecontainer has been replaced.

According to an even further aspect of the invention, a refusemanagement system has a refuse container associated with a compactor forcompacting refuse in the container at a local position, a localcontroller for receiving and transmitting signals from the compactor,and a processor at a remote position for receiving and processingsignals from the local controller. A transmitter/receiver is positionedat each of the local and remote positions for establishing two-waycommunication between the local controller and the remote processor suchthat the controller and processor can each send and receive signals fromeach other. A local display is in communication with the controller fordisplaying signals from the controller and signals received in thecontroller from the processor to thereby display container condition. Akeypad can be provided with the local display and controller forentering data into the controller and displaying data on the display.Preferably, the keypad has function keys for entering and displayingdata representative of system parameters and conditions, and scroll keysfor scrolling through the data on the display. The display can alsoinclude a warning light for indicating when at least one systemparameter has been met or exceeded.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings inwhich:

FIG. 1 is a diagrammatic representation of a plurality of refusecompactor systems according to the invention arranged for communicationbetween a remote computer;

FIG. 2 is a block diagram illustrating a method according to theinvention for determining the fullness of the refuse container;

FIG. 2A is a block diagram of a method for predicting when the refusecontained will be full;

FIG. 3 is a block diagram illustrating a method according to theinvention for determining if the refuse container has been removed;

FIG. 4 is a side elevational view of a self-contained unit formonitoring and displaying various system parameters; and

FIG. 5 is an enlarged view of the display and keypad of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, a refuse management system 10 includes aplurality of refuse compactor systems 12 arranged for communicationbetween a remote computer 14 via phone lines 16. Each refuse compactorsystem 12 includes a refuse container 18 removably attached to acompactor 20. The compactor 20 is in communication with a programmablelogic controller (PLC) or management computer 22. Signals representingcompactor actuation and pressure are received, stored, and processed inthe PLC 22. A proximity detector 24, such as an electro-optical sensor,sends a signal to the PLC 22 when the container is removed for emptyingand informs the PLC when the container is present. The PLC generates andtransmits a number of different parameters based on these signals whenpolled by a remote computer 14 that includes a central processor. Oneparameter generated is the container status, which indicates whether thecontainer is present or missing based on a signal from proximity sensor24. Another parameter generated is the current pressure P, which ismeasured from a pressure transducer (not shown) in the compactorhydraulic lines and is reflective of the current operation of thecompactor. The current pressure is usually the residual pressure in thelines unless the compactor is running. Other parameters generatedinclude the following:

(1) The average pressure P_(A), which is the average of a plurality ofpressure readings during compactor use. (Preferably, the pressure isaveraged over ten readings; however, any number of readings can be usedto generate the average);

(2) The last pressure P_(L), which is the last pressure reading duringcompactor use;

(3) The high pressure P_(H), which is the highest pressure recordedduring compactor use since the container was removed;

(4) The time T_(O) at which the container was removed for unloading; and

(5) The average number of uses U_(A) per day, hour, shift, etc. Theaverage number of uses for a particular day U_(A) is determined bydividing the number of compactor uses for the same day each week for thenumber of weeks recorded. For example, if compactor use for each Mondayover a four-week period is 14, 18, 20, and 16, the average number ofuses for a Monday would be 17. Similar calculations can be made for aparticular hour or shift for each day.

A display 26 is in electrical communication with the PLC. The display 26is capable of displaying information such as when the hauler has beenordered and when the container is full. This information is relayed viathe PLC from the remote computer 14. Other parameters as described abovemay also be displayed. The remote computer can send messages, such as"Transportation ordered for (date)", "Container Full", etc., via thephone line 16 and PLC 22 to the display 26. The display 26 may be alight, such as a strobe light that is illuminated when transportation isbeing ordered and/or when a fault has occurred, or may be of thealpha-numeric, LCD, LED, or CRT type depending on what information is tobe communicated.

With reference now to FIG. 2, a method for determining when the refusecontainer is full will now be described. When the compactor 20 isactuated for compacting refuse in the container 18, a pressure signalP_(i) is generated from the pressure transducer (not shown) within thecompactor hydraulic lines and relayed to the PLC, as shown at block 30.If the container was recently emptied, a counter in the PLC isincremented by one as shown at block 32. If the count from the counteris not equal to the predetermined count n, then another pressure readingP_(i+1) is taken, as shown at block 34. This process continues until thecounter is equal to the predetermined count n. When the counter is equalto the predetermined count, an average pressure reading P_(A) iscalculated for the last n readings as shown at block 36. In a preferredembodiment, the average pressure P_(A) is calculated for the last tenreadings. In block 38, it is determined whether the average pressure isequal to or greater than a predetermined maximum operation pressureP_(M), which for most compactors is in the range of about 1000 psi toabout 2000 psi. This maximum operating pressure can be programmed intothe PLC or computer through a computer keyboard (not shown) or a keypad(FIGS. 4, 5). As the container fills, the compactor must workincreasingly harder. The amount of pressure sensed by the pressuretransducer is reflective of how hard the compactor is working. Once thepressure reaches the maximum operating pressure P_(M) the container isfull and must be emptied. It is important to note that the pressure isaveraged over a plurality of pressure measurements since any onepressure measurement may not be reflective of the amount of refuse inthe container. For example, it is not uncommon for wooden pallets orother like materials to be thrown into the container. The compactor mustwork harder when actuated to compact these materials and therefore givea pressure reading that is not indicative of the container condition,albeit an accurate pressure reading. If it is determined in block 38that the average pressure is less than the upper limit, the compactorpressure is again measured as shown at block 40. Since there are alreadyn pressure measurements, the oldest pressure measurement is dropped, anda new average is calculated in block 36. If it is determined in block 38that the average pressure is equal to or greater than the upper limit,the result is displayed on display 26 as shown at block 42. This resultis also transmitted to the remote computer 14 when the PLC 22 is polled.When a hauler is ordered to empty the container, the display 26 isupdated via the remote computer and PLC to relay this status to the enduser. This information can be relayed not only to a local display orwarning light, but also by fax, telephone, pager, etc., to the end useror other person.

In addition to notifying the end users and haulers when the container isfull, the system 12 projects the time at which the container 18 will befull so that service can be scheduled in advance as shown in FIG. 2A. Inorder to project when the container will be full, the average pressureP_(A) calculated from the last n pressure measurements is divided by themaximum operating pressure P_(M) of the compactor to give the pressurepercentage P_(R), block 43. This percentage P_(R) is then subtractedfrom one (1) and the remainder is multiplied by the pull average usageU_(PA) that the compactor is used between container pulls to give anumber of remaining uses U_(R), on average, before the container isfull, block 44. The pull average usage U_(PA) is equal to the totalnumber of times that the compactor is used divided by the total numberof container pulls since installation of the system. When the system isfirst installed, U_(PA) can be estimated until the container is pulledfor the first time. The pull average usage U_(PA), becomes increasinglyaccurate over several pull cycles, but may continuously change, due toinconsistent use between pulls by end users. The amount of remainingtime T_(R) (expressed in days, hours, etc.) can then be calculated bysubtracting the summation of an average usage U_(TP), for each timeperiod from the remaining number of uses U_(R), blocks 45, 46 and 47.For example, in a compactor having a maximum operating pressure P_(M) of1600 psi and an average usage U_(A) of 150 times per pull, and at theend of the day an average pressure P_(A) of 1400 psi is recorded, thetotal number of remaining compactor uses U_(R) would be(1-1400÷1600)·150=19. Thus, approximately 19 uses on average, remainbefore the compactor is full. If the following three days each have anaverage usage U_(TP) of 10, 7 and 9 times, respectively, the containerwill be full on the third day after operating the compactor only one ortwo times. The computer at the remote location or the local PLC may thensend this information to the display 26, a facsimile machine, pager,etc., indicating the current amount of uses remaining, the timeremaining until the container is full, the scheduled time for servicingthe container, block 48. This feature advantageously permits the enduser to schedule around the container removal to thereby avoid or reduceany inconvenience.

The average pressure P_(A) can also be used to estimate the amount ofused and unused space in the container. As the container fills, thecompactor must work harder to compress the refuse material. The pressurein the compactor hydraulic lines is reflective of how hard the compactoris working, and can thus be used as an accurate determination of howmuch compacted refuse is in the container The amount or percentage ofused space in the container is determined by dividing the averagepressure P_(A) by the maximum operating pressure P_(M) to give thepressure percentage P_(R). The pressure percentage P_(R) is reflectiveof the amount of used space in the container and can be displayed atboth the local and remote locations. The amount of remaining space inthe container can be determined by subtracting the pressure percentageP_(R) from one (1).

Referring now to FIG. 3, a method for determining if the container hasbeen removed will now be described. Once the hauler has been scheduled,or at any other predetermined time, it is determined at block 50 whetherthe proximity sensor 24 has been actuated. Actuation of the proximitysensor 24 is reflective of container removal. Once the sensor 24 hasbeen actuated, the time that the container was removed is set to thetime of sensor actuation as shown at block 52. Certain of the parametersare then reset at block 54. These parameters include the currentpressure reading P, average pressure calculated P_(A), last pressureP_(L), high pressure P_(H) since container pulled, and the pressurereading counter. The pressure is again monitored during use and themethod in FIG. 2 is again repeated.

If, however, the sensor at block 50 was not actuated, the compactorpressure during use is again measured as shown at block 56. At block 57,it is then determined if the average pressure P_(A) is above apredetermined upper pull set point P_(UP), which is preferably aboutmidway between the predetermined upper limit P_(M) and a predeterminedlower pull or "no loads" set point P_(LP). For most compactor systems,this upper pull set point P_(UP) will be in the range of about 500 to800 p.s.i. Of course, other values between the lower pull set pointP_(LP) and upper limit P_(M) can be entered into the PLC or computer. Ifthe average pressure reading P_(A) is below the upper pull set pointP_(UP), it is concluded that the container has not been pulled, and thecontainer is again monitored at block 50 At block 58, it is thendetermined if the last pressure measurement is below the lower pull setpoint P_(LP). As described above, when the container is empty or nearempty, the compactor is not required to work hard. The amount ofpressure sensed by the pressure transducer is reflective of how hard thecompactor is working. Once the pressure is below the lower pull setpoint P_(LP), there exists the possibility that the container may havebeen removed, emptied, and replaced without being detected by theproximity sensor 24. A number of different factors may prohibit thesensor 24 from actuating. For example, the sensor may be dysfunctionalor improperly installed. More often, the PLC that monitors and displaysthe compactor condition is electrically connected to the compactor powersupply. The compactor and its associated PLC are sometimes disconnectedfrom the electrical source when the container is separated from thecompactor, and reconnected after the empty container and compactor arerejoined. An end user or truck driver may unwittingly disconnect theelectrical source, reasoning that an impaired compactor would be saferwhile detached from the container. In any event, the proximity sensorunder these circumstances does not generate a signal to reset thecurrent values. As a result, the current values are not reflective ofthe current container condition and can therefore be interpretederroneously.

If the last pressure reading is not below the lower pull set pointP_(LP) at block 58, it can be fairly assumed that the container has notyet been removed and emptied. The PLC waits until the sensor 24 isactuated or until the compactor 20 is used again at block 50.

Once it has been determined that the last pressure reading is below thepreset lower limit P_(LP), the time at which the last detected pressurewas measured is saved, as shown at block 60. It is then determined atblock 62 if the average pressure P_(A) for the last n readings is lowerthan the preset lower limit. If not, the PLC waits unit the sensor 24 isactuated or until the compactor 20 is used at block 50. It is importantto note that the pressure is averaged over a plurality of pressuremeasurement since any one pressure measurement may not be reflective ofthe amount of refuse in the container. For example, assuming that thecontainer has not yet been emptied, a low pressure measurement may bethe result of actuating the compactor without adding additional refuseto the container. Since the refuse in the container is alreadycompacted, the compactor does not work as hard. If, after n pressuremeasurements, the average pressure drops below the preset lower limit,it is a good indication that the container had been previously pulledwithout detection. As a precautionary measure, it is determined in block63 if a minimum usage set point U_(M) has been exceeded. The minimumusage set point U_(M) is a number that can be entered into the PLC thatis reflective of the number of times that the compactor is actuated froman empty container condition to a full container condition. This numbercan be accurately determined over several container loading and dumpingcycles. If the minimum usage set point U_(M) is not exceeded, the sensoragain detects if the container is pulled at block 50. If U_(M) isexceeded, the saved time of the first pressure reading to drop below thepreset lower limit P_(LP) is used at block 64 to set the time at whichthe container was removed. Certain of the parameters are then reset atblock 66 as of the saved time. These parameters include the currentpressure reading, average pressure calculated P_(A), last pressureP_(L), high pressure P_(H) since container pulled, and the pressurereading counter. The pressure is again monitored during use and themethod in FIG. 2 is again repeated.

Referring now to FIGS. 4 and 5, a self-contained unit 70 that can beinstalled on or near the compactor includes a PLC of the type heretoforedescribed and a display module 74. A modem is also provided in the unit70 for communication between the unit 70 and the remote computer.Alternatively, the modem is unnecessary when the unit is to be solelyoperated and controlled locally. The unit 70 includes a housing 72 witha data entry and display module 74 mounted to a front surface 76thereof. A warning strobe light 78 is mounted to a top surface 80 of thehousing.

With particular reference now to FIG. 5, the data entry/display module74 comprises a keypad 82 having a plurality of function keys 84 (F1-F6),an up key 86, and a down key 88. A display 90 of the LED or LCD type iscontrolled by the microcomputer based on information received from thecompactor and function keys. The F1 key functions as an "Enter" key thatis pressed after inputting information into the module 74 through thekeypad. The F2 key functions as an event and fault log key to displaythe current conditions within the compactor. When the strobe light isflashing, the display will show the event or fault associated with theflashing. The F3 key, when pressed, causes the display to show what timethe container was pulled for dumping, how many times the compactor hasbeen actuated since the last pull of the container, and the averagepressure in the container during the last 10 uses. The F4 key is asecurity key that is pressed before entering a code. The code is enteredby pressing a combination of function keys and/or the up and down keysin a particular sequence. In this manner, the user can gain access toand change the preset pressure limits, current date, time, etc., storedwithin the computer memory. The F5 key, when pressed, resets the displayback to the default screen and stops the strobe light from flashing. TheF6 key is pressed to gain access for adjusting the data displayed on thescreen, such as the date, time, set points, etc. This key can be pressedseveral times to scroll the display to the desired information. The upand down keys are used to actually change the date, time, set points,etc., displayed on the screen.

In operation, and by way of example, when the F5 key is pressed, thedefault screen will appear on the display. By sequentially pressing theup key 86, the default screen scrolls to display the followingparameters: 1) current date; 2) current time; 3) the number of times thecompactor has been used since the container was last pulled; 4) theaverage pressure P_(A) in the container (as measured by the hydraulicpressure transducer) during the last ten compactor uses; 5) the pressureP_(L) in the container during the last compactor use; 6) the averagecompactor usage per pull U_(PA) ; 7) the percentage of occupiedcontainer space, which is reflective of the pressure percentage asdetermined by P_(A) ÷P_(M) ; 8) the percentage of unused containerspace; 9) the number of compactor uses left U_(R) ; and 10-16) thenumber of uses U_(TP) for each day of the week, respectively. Theseparameters can also be accessed in reverse order by pressing the downkey 88.

When the F2 key is pressed, the Event and Fault Log is displayed. Bypressing the up or down keys, the last 10 events that have been recordedin the management unit 70 will be displayed sequentially. Although tenevents are preferred, it will be understood that more or less events canbe displayed. The Event and Fault Log is useful in determining if andwhere a malfunction has occurred during operation. Some of the eventsthat can be displayed are: 1) motor overload, which is detected thefirst time that the hydraulic motor (not shown) on the compactor and isreflective of blown overload heaters on the starter (not shown) when anattempt has been made to start the hydraulic motor; 2) over averagepressure, which tells the user that the preset maximum limit P_(M) hasbeen exceeded; and 3) over-usage goal, which informs the user of thenumber of compactor usages that exceed the preset usage set point. Thepreset usage set point can be entered and periodically changed so as toreflect the average usage U_(A) over several container dumping cycles.

When the F3 key is pressed, the Container Pulled Record Log will appearon the display. Again, by pressing the up and down keys, the date,average compactor pressure P_(A), and the number of compactor uses foreach of the last ten pulls will be sequentially displayed.

Certain predetermined set points and limits, as described above, andother information can be entered by a user or technician once thesecurity code has been properly entered. The information that can bechanged includes: 1) the maximum pressure P_(M) or upper limit at whichthe particular compactor can operate; 2) the current month and year; 3)the current date and hour; 4) the current day and minute; 5) the usagealarm set point, which is the estimated number of times that thecompactor should be used during a predetermined time interval, such as asingle day or between container pulls. When this number is exceededduring the time interval, the warning light will flash and the displaywill show the amount of over-usage; 6) the average upper pressure alarm,i.e. when the average pressure P_(A) on the compactor reaches the upperset point P_(M), the average pressure will be shown on the display andthe warning light will flash; 7) the last extend time (in seconds) forthe compactor ram, which is the time measured between actuation of thehydraulic pump and a predetermined pressure in the hydraulic lines orthe tripping of an extend limit switch in the compactor, and the lastretract time (in seconds) for the compactor ram, which is the timemeasured between reversal of the compactor ram direction and thetripping of a retract limit switch in the compactor; 8) the retractfault time, which in the preferred embodiment is set at ten secondslonger than the last retract time; 9) the extend fault time, which inthe preferred embodiment is set at ten seconds longer than the lastextend time; 10) the extend cut-off time, which in the preferredembodiment is set at one second below the last extend time; 11) theupper pull set point P_(UP), which is the pressure set point above whichthe compactor must rise in order to initiate the resetting of certainparameters once it is determined that the container has been pulled, asdescribed above; 12) the minimum usage set point U_(M), which is used incombination with the upper pull set point P_(UP) to reset the certainparameters and dictates the minimum number of times that the compactormust be used before the container has been pulled, as described above;and 13) the lower pull set point P_(LP), which, as described above,dictates the minimum average pressure below which the compactor mustfall in order to signal that the container may have been dumped.

The monitoring of extend and retract times of the compactor ram, asdescribed above, is important in determining if the compactor is workingproperly. A delay in the extend and/or retract times may indicate thatthe guide shoes on the outside of the ram are worn and should bereplaced, or that there is some other problem that is delaying the ramduring extension or retraction. Likewise, the extend cut-off time shouldnot be set at a value that is much less than the last extend time, sincesome compactors rely on the maximum pressure P_(M) to reverse the ram onevery stroke. Thus, only the data relating to the working pressure ofthe compactor is collected. Even if the compactor is operated withoutadding additional waste material to the container, the ram extend timeis normally not greater than the previous extend time.

Although the display of various parameters has been described inparticular detail with respect to the local unit 70 of FIGS. 4 and 5, itis to be understood that such parameters can also be displayed (andchanged where appropriate) on a display that is remote from thecompactor, such as at the remote computer. All of the information, ordifferent combinations thereof, can be displayed and/or printedsimultaneously at the remote location.

As described above, the local display module 74 and warning light 78 canbe accessed by the remote computer to let the end user know that servicehas been arranged at a particular time and/or date, such as when thecontainer is projected to be full, or during compactor malfunction. Ithas been found that many end users prefer not to be preoccupied withoperation of the compactor until the time approaches to pull thecontainer. For this purpose, the warning light 78 can be actuated eitherfrom the remote location or locally to notify a user that the containeris almost fill, container dumping has been scheduled, compactor servicehas been ordered, a malfunction in compactor operation has occurred, anyof the preset limits as described above has been exceeded, or anycombination of the above. When the warning light is flashing, the usercan quickly ascertain the particular function or functions that causedthe light to flash by pushing the appropriate keys on the keypad. Inthis manner, the end user has as much control as desired over thecompactor and container operation.

Reasonable variation and modification are possible within the spirit ofthe foregoing specification and drawings without departing from thescope of the invention.

The embodiments for which an exclusive property or privilege is claimedare defined as follows:
 1. A method of determining the fill condition ofa refuse container to which a compactor is attached for compacting therefuse, the method including the steps of:measuring at least onepressure applied to the container by the compactor during at least onecompression performed by the compactor; and calculating a first-pressurepercentage with a processor by dividing the measured pressure by apredetermined pressure limit, the first pressure percentage beingreflective of the used space of the refuse container, characterizedby:calculating a second pressure percentage with the processor bysubtracting the first pressure percentage from unity, wherein the secondpressure percentage is reflective of the amount of space available inthe refuse container for holding more refuse.
 2. The method according toclaim 1, wherein the step of measuring at least one pressure includesmeasuring a plurality of pressures during a corresponding plurality ofcompactor operations, and further comprising the step of determining anaverage pressure from the plurality of pressures, and wherein the stepof calculating the first pressure percentage includes dividing theaverage pressure by the predetermined pressure limit.
 3. The methodaccording to claim 2, further comprising the steps of:determining afirst usage count of the compactor during a pull interval between anempty container condition and a full container condition when thecontainer is pulled for dumping by monitoring how often the compactor isactuated to compact the waste during the pull internal; and determininga remaining usage count of the compactor by multiplying the secondpressure percentage by the first usage count.
 4. The method according toclaim 3, further comprising the steps of:determining a plurality ofsecond usage counts of the compactor for a corresponding plurality ofsequential time intervals; and forecasting a time when the containerwill be full with the processor by comparing the remaining usage countwith at least one of the second usage counts.
 5. The method according toclaim 4, wherein the first usage count is an average first usage counttaken over a plurality of pull intervals; and wherein the plurality ofsequential time intervals defines a time group; and wherein each of thesecond usage counts is an average second usage count taken over aplurality of time groups.
 6. The method according to claim 5, whereineach time interval is a day and each time group is a week.
 7. The methodaccording to claim 5, wherein each time interval is an hour and eachtime group is a work shift.
 8. The method according to claim 1, whereinthe predetermined pressure limit is the maximum pressure applied by thecompactor when the container is full.
 9. A method for detecting when arefuse container has been replaced in a refuse management system havinga refuse container associated with a compactor for compacting refuse inthe container, the method comprising the steps of:operating thecompactor to compact refuse in the container; measuring a plurality ofpressures applied to the container by the compactor during a pluralityof corresponding compactor operations; calculating an average pressurefor the plurality of measured pressures with a processor; comparing theaverage pressure with a low pressure set point with the processor; anddetermining with the processor that the container has been replaced ifthe average pressure is below the low pressure set point.
 10. The methodaccording to claim 9, further comprising comparing compactor usage witha minimum usage set point with the processor; and wherein thedetermining step includes determining that the container has beenreplaced if the compactor usage is above the minimum usage set point.11. The method according to claim 10, wherein the refuse managementsystem comprises a proximity sensor for sensing the presence of thecontainer; and further comprising the step of sensing the containerpresence with the proximity sensor before measuring the plurality ofcompactor pressures.
 12. The method according to claim 9, wherein therefuse management system comprises a proximity sensor for sensing thepresence of the container; and further comprising the step of sensingthe container presence with the proximity sensor before sensing theplurality of compactor pressures.
 13. A method for predicting when arefuse container will be full, the refuse container being attached to acompactor that compacts the refuse contained in the container, saidmethod including the steps of:monitoring when the compactor is actuatedso as to maintain a count for at least one time interval of the numberof times the compactor is used in that at least one time interval;calculating the average usage of the compactor with a processor for theat least one time interval, said average usage calculation based on thecount obtained of how often the compactor was used during a plurality ofdifferent ones of the at least one time interval; determining thefullness of the refuse container with the processor; calculate theremaining uses of the refuse container based on the fullness of therefuse container with the processor; and determining when the refusecontainer will be full with the processor by subtracting from thecalculated remaining uses of the container the calculated average usageof the refuse container from the current time interval for consecutivetime intervals thereafter until the calculated remaining uses falls tozero, the time interval in which the remaining uses falls to zero beingthe time interval at which the refuse container is predicted to be full.14. The method of predicting when a refuse container will be full ofclaim 13, wherein said step of determining refuse container fullness isperformed by monitoring the pressure of the compactor.
 15. The method ofpredicting when a refuse container will be full of claim 14, whereinsaid step of determining refuse container fullness is performed bycomparing the pressure of the compactor to a maximum compactor pressure.16. The method of predicting when a refuse container will be full ofclaims 15, wherein said step of determining the remaining uses of therefuse container includes: determining the average number of uses of thecontainer over a plurality of pull intervals, each pull interval beingan interval between when the refuse container is empty and when therefuse container is full and determining the remaining uses based on theaverage number of uses of the refuse container and the current measureof waste container fullness.
 17. The method of predicting when a refusecontainer will be full of claim 13, wherein said step of determiningwaste container fullness is performed by monitoring the pressure of thecompactor and determining the average pressure of the compactor over aplurality of uses.
 18. The method of predicting when a refuse containerwill be full of claim 17, wherein said step of determining refusecontainer fullness is performed by comparing the average pressure of thecompactor to a maximum compactor pressure.
 19. The method of predictingwhen a refuse container will be full of claims 17, wherein said step ofdetermining the remaining uses of the refuse container includes:determining the average number of uses of the container and determiningthe remaining uses based on the average number of uses of the refusecontainer and the current measure of waste container fullness.
 20. Themethod of predicting when a refuse container will be full of claim 13,wherein said step of determining the remaining uses of the refusecontainer comprises the steps of:determining an average number of usesfor the refuse container over a plurality of pull intervals, each pullinterval being an interval between, when the refuse container is emptyand when the refuse container is full; and basing the determination ofthe remaining uses of the refuse container on said determination ofrefuse container fullness and said average number of uses for the refusecontainer.
 21. The method of predicting when a refuse container will befull of claim 13, wherein the average uses of the compactor arecalculated for a plurality of different, chronologically consecutivetime intervals.
 22. The method of predicting when a refuse containerwill be full of claim 21, wherein the time intervals are one from thegroup consisting of: days; hours; and work shifts.